The present invention generally relates to a system for activating hydraulic actuators and more particularly to a system including a hydraulic master cylinder for activating a remotely positioned slave cylinder to operate a clutch throw-out bearing.
The present invention replaces the mechanical clutch release system utilized in many manual transmission vehicles. This manual release system comprises a number of assemblies, such as: a clutch pedal assembly, a clutch operating cable and bushings and guides therefor, a clutch fork operating arm, a clutch fork operating shaft and associated bearings and bushings, a clutch fork, a throw-out bearing retaining pin, and the throw-out bearing cage and bearing assembly. The above system requires detailed on-the-line assembly of all interfacing mechanical components, along with the rather detailed assembly of the various associated sub-assemblies which make up the entire system. As can be seen from the above the mechanical clutch release system is relatively complicated, and relatively inefficient due to the interaction of and work losses between the various assemblies. Further, the clutch operating cable itself is a fairly delicate assembly that requires dedicated space and alignment to prevent kinking or relatively sharp bends which further detract from the systems' mechanical efficiency.
The present invention provides a hydraulic clutch actuator system which comprises a clutch pedal assembly of somewhat simpler construction than present systems. This advantageous construction is achieved by eliminating such items as the clutch pedal rod which links the clutch pedal to a torque shaft and the various springs, such as the over-center spring or pull-back spring, and various bracket members associated therewith. The present system further includes a hydraulic master cylinder located proximate the clutch pedal which is connected to a slave cylinder of relatively simple construction. In the preferred embodiment of the invention, the system comprises a pre-charged system utilizing quick connect/disconnect couplings to attach a filled hydraulic line that links the master cylinder and slave cylinder. Further prior systems with utilize remote master and slave cylinders often use diaphragms for pressurizing the fluid therein. These diaphragms often rip and leak because of the shear forces generated. The present invention provides a solution to such problems.
Accordingly, the invention comprises:
a hydraulic fluid system for engaging and disengaging clutches, such as clutches for manual transmissions comprising: a master cylinder capable of pressurizing fluid upon demand, and a slave cylinder, remote from said master cylinder for engaging the clutch. The slave cylinder comprises:
an axially expandable, variable volume activation chamber defined by a rolling diaphragm and means for securing the diaphragm. The slave cylinder further includes means for receiving pressurized fluid and for communicating same to the diaphragm; means for providing an annular support proximate to and exterior of the diaphragm, and a cup shaped piston loosely fitted to the annular support between the annular support and a portion of the diaphragm, for decoupling the diaphragm from the throw-out bearing. The walls of the piston provide first and second annular spaces into which portions of the diaphragm can enter as a throw-out bearing moves in a direction to compress the diaphragm. The invention further comprises a master cylinder for pressurizing the slave cylinder, a pre-charged hydraulic line interconnecting the master cylinder and slave cylinder and a slack adjusting or compensating mechanism for providing a predetermined free-play for a clutch pedal to compensate for the movement of various components due to the wearing of the friction plate of the clutch.